Plants

Plants are any kind of vegetation. However, plant-related mutations are quite frequent in the Troll movies. When Torok begins transforming the Potter family's neighbors into fairy creatures, their bodies first mutate into plant-like pods, out of which vines ant other plants finally burst. (Troll)

The Goblins of Nilbog, being vegetarians, used a green herbal concoction to transform their victims into half-human, half-plants. They could then eat the human fauna. Arnold was partially converted into a tree in this manner. (Troll 2)

Killer plants, as seen in "The Crawlers".

The root system of the forest near Smallsville was mutated by radioactive waste, illegally dumped there by a nearby power plant. The roots became aggressive killers, which ensnare Human passerby and crush them to death. (The Crawlers)